Strange behaviour of error CS0246 in Unity

Hi, I am implementing some C# code in my Unity in UniScite, however it shows following error “error CS0246: The type or namespace name `RigidBody’ could not be found.” even thought I have put using UnityEngine and System.Collections at the top. What may be the cause to it?

Shouldn’t the Type be “Rigidbody”? lowercase b on body